<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>01_重置默认样式</title>
    <!-- <link rel="stylesheet" href="./reset.css"> -->
    <!-- <link rel="stylesheet" href="./normalize.css"> -->
    <style>
        .demo {
            background-color: gray;
        }
    </style>
</head>
<body>
    <div class="demo">123</div>
    <h1>一级标题</h1>
    <h2>二级标题</h2>
    <h3>三级标题</h3>
    <h4>四级标题</h4>
    <a href="#">去百度</a>
    <ul>
        <li>张三</li>
        <li>李四</li>
        <li>王五</li>
    </ul>
</body>
</html>